The present application claims priority of Chinese patent application Serial No. 200710118200.7, filed Jul. 2, 2007, the content of which is hereby incorporated by reference in its entirety.
During scan imaging, an accelerator generates high-energy X-ray pulses, which penetrate through the object under scan. Detector arrays with high sensitivity receive the X-rays, and convert them into an electrical signal for output. Then, columns of digital images are generated in real time by an image acquisition subsystem. When the entire scanning process completes, a whole image for the scanned object will be obtained at a system control station.
In an imaging system, a main function of an accelerator is to generate X-ray pulses under control. A detector converts the X-rays penetrating through a scanned object into an analog electrical signal, and then sends the signal to an image acquisition system. The image acquisition system then converts the analog electrical signal acquired from the detector system into a digital signal. Depending on the digital signal, an image is established by an image acquisition station.
In the existing scan imaging, the scanning speed thereof should not be too fast, approximately at 4 km/h. With the increase of the inspection requirements, a system that can achieve high-speed scan imaging is urgently needed, which may be used for security inspection, for example for cars on land ports and various checkpoints without parking, or for low-speed check on trains and the like.
Particularly, how to achieve high-speed acquisition for data when a car is running very fast, such as at a speed of 30 km per hour, is a main confronted problem. There are two kinds of commonly employed data acquisition systems applied in the inspection systems for X-rays source in the same field, particularly as follows: 1) designing a dedicated transmission data bus according to the system structure; 2) transmitting data using the field bus technology. Considering the inspection system for high-speed acquisition, the design of a dedicated data transmission bus is disadvantageous for extending. When the number of detecting units is increased, the amount of data transmission on the original bus can not meet requirements, and it is needed to redesign the system. However, the field bus technology applied in the radiation inspection systems has a lower transmission rate, such as CAN bus, the highest transmission rate thereof is 1 Mbps, and can not satisfy the tasks for real-time high-speed acquisition and transmission of mass data.